The predominant activity of the section has been the continuing studies of families with specific types of cancer such as melanoma, nevoid basal cell carcinoma syndrome, ovarian cancer, chronic lymphocytic leukemia, and Hodgkin's disease. In addition, more traditional epidemiologic studies such as case- control and cohort studies of the etiology of lung cancer, cutaneous melanoma, and leukemia after ovarian cancer have continued. Most of these have had a biochemical component. A collaborative study of the risk of cancer related to dioxin exposure in Seveso, Italy, was begun. New initiatives include interdisciplinary studies of breast, prostate, bladder, and endometrial cancers, and a cohort study of leukemia following epipodophyllotoxin exposure.